This invention relates to a novel diacetylene-nylon salt compound, to a method for producing two-dimensional macromolecular crystals having covalent bond chains oriented and crystallized in two-dimensional directions by the solid-state polymerization of the diacetylene moiety and the solid-state polycondensation of the nylon salt moiety respectively of the aforementioned diacetylene-nylon salt compound, and to a method for producing a shaped article of high rigidity by filling a mold with the aforementioned diacetylene-nylon salt compound and subjecting the compound in the mold to simultaneous application of heat and pressure.
In recent years, efforts have been devoted to the development of new materials in various fields. For example, research and development activities are being pursued in search of high-performance macromolecular materials possessing high strength and high modulus of elasticity and consequently expected to find extensive utility as heavy-duty materials of light weight and ready processibility capable of taking the place of metallic materials and inorganic materials.
Heretofore, as macromolecular materials enjoying high strength and high modulus of elasticity, whisker crystals of polyoxymethylene and fibrously oriented crystals of rigid macromolecules of polyarylamides such as, for example, the products of DuPont marketed under trademarks "Kevlar" and "Nomex" have found widespread acceptance. They range from several GPa's (gigapascal) to ten-odd GPa's in strength and from some tens of GPa's to about 100 GPa's in modulus of elasticity. For the purpose of conferring enhanced strength and modulus of elasticity upon these macromolecular materials, various studies are being continued in search of techniques capable of orienting and crystallizing these macromolecular materials. So far, for example, various techniques such as the superstretching method, the liquid crystal spinning method, the gel spinning method, the hot gel stretching method, and the carbonation method have been developed. None of these methods, however, is capable of producing perfect crystals. The macromolecular materials produced by these methods, therefore, are not necessarily fully satisfactory with respect to strength and modulus of elasticity.
It has been known that the diacetylene compounds represented by the formula: EQU R--C.tbd.C--C.tbd.C--R
when the substituents R are properly selected, exhibit an ability of solid-state polymerization which, upon excitation of the crystals thereof with heat, ultraviolet light, or .gamma. ray, converts the compounds into macromolecular compounds with a conjugated main-chain. The macromolecular compounds obtained by this method, namely polydiacetylenes, are characterized by being perfect single crystals faithfully reflecting the crystalline arrangement of their respective monomers. It has been reported that such macromolecular compounds exhibit a modulus of elasticity approximating 60 GPa's in the direction in which their macromolecular chains are oriented ["Polymer", vol. 24, pp. 1023-1030, 1983].
Diamond is the strongest of the materials existing in the natural world. It has been theoretically demonstrated that in the design of molecular configuration for macromolecular materials possessing high strength and high modulus of elasticity, it is necessary to prepare single crystals which have small cross sections for occupation by molecules and possess polydimensional covalent bonds. Actually, however, no single crystal of the foregoing description has yet been discovered.
The highly oriented highly crystalline macromolecular compounds heretofore synthesized, molded, and processed for the purpose of obtaining materials of high strength invariably are one-dimensional chain macromolecular compounds. Though they exhibit fairly high levels of strength and modulus of elasticity in the direction of their molecular chains, they have a disadvantage that they are deficient in strength and modulus of elasticity in the direction perpendicular thereto. The polydiacetylenes obtained in the form of perfect single crystals as mentioned above have a disadvantage that they gain in brittleness as they are cleaved apart into fibers in the direction perpendicular to the directon of molecular chains, for example.
Among the heretofore known macromolecular compounds possessing polydimensional covalent bonds, there are counted those which are synthesized as by the intermolecular cross-linking method. By this method, it is extremely difficult to attain high crystallization of a compound. The method is barely capable of producing an amorphous reticular macromolecular compound.
As described above, no macromolecular material isotropically exhibiting high strength and high modulus of elasticity has yet been discovered. In the circumstance, the desirability of developing a macromolecular material of the foregoing description has found enthusiastic recognition.
An object of this invention is to provide a macromolecular material which isotropically exhibits high strength and high modulus of elasticity.